Both the G4 and G3 have five layer Gortex but on the G3 it only goes up to above the knee. On the G4 is goes up to the waist, I sit down on rocks, trees, dirt, whatever happens to be on the streamside when I get tired. The G4's Also have zippered pockets for hands and a few other minute features I cant think of right now. For a $100 difference I spent the extra cash as it was worth it for me in the end.